There is a wide range of connection standards used today in the fueling industry. This ranges from threaded connections using standards such as National Pipe Thread Taper (NPT), which is a U.S. standard for tapered threads used on threaded pipes and fittings to prevent leaks, to quick connect fittings such as cam locks and dry-break interface standards. Often times it is required to connect two different standards and an adapter is required to ensure proper sealing of both connection types to prevent any possible leaks.
A first connection standard for fueling dispensers can be found in U.S. Pat. No. 4,441,533 (Snyder) which describes an automatic fuel dispenser for the fueling of locomotive fuel tanks, and the connection standard (aka a twist-lock coupling) used to connect the dispenser with the fill tube of the fuel tank on the locomotive. To accomplish this connection, a fill pipe receiver is installed into the fill tube of the locomotive fuel tank. The fill pipe receiver contains an outer ring with two openings or “gaps” designed to accommodate the attachment portion of the fuel dispenser. The Snyder fuel dispenser is provided with an outer ring-like shoulder which cooperates with a compressing seal and locking element containing two L-shaped attachment points. The L-shaped attachment points of the fuel dispenser are designed to engage with the outer ring of the receiver by sliding through the gaps until they are below the outer ring and then turning in a first direction to form a locked-on and sealed connection between the fuel dispenser and receiver. To disconnect the fuel dispenser from the receiver, the outer ring of the fuel dispenser is turned in a second direction and the fuel dispenser is removed from the receiver.
A second connection standard for fueling dispensers can be found in aviation military specification standard (MS 24484), aka a dry-break coupling, a dry aviation coupling, and a dry-disconnect coupling. Dry-break couplings are commonly used for under wing fueling of aircraft. Dry-break couplings cannot be “opened” or otherwise allow fuel to flow therethrough until the dry-break coupling has been securely connected to a mating receptacle.
A dry-break coupling uses a different connection method and size than that specified in twist-lock couplings such as U.S. Pat. No. 4,441,533, therefore making dry-break couplings generally incompatible with twist-lock coupling-style fuel receivers (which are configured for use with twist-lock coupling-style fuel dispensers).